Method of manufacturing hollow product using draft angle

ABSTRACT

A method of manufacturing a hollow product using a draft angle is disclosed. A method of manufacturing a hollow product using a draft angle refers to a method of manufacturing a hollow product using a core having a draft angle. The core is formed to protrude in one direction and has an outer surface at a perimeter of a protruding portion of the core, the outer surface of the core forms a slope with respect to the one direction, and a cross-sectional area of the core decreases as the core goes toward a protruding direction. The method comprises disposing a mold to be spaced apart from the outer surface of the core, disposing a hollow tube between the core and the mold, injecting a molten metal into a space between the core and the mold, and removing the core when the molten metal is solidified and the hollow product is molded.

TECHNICAL FIELD

The present disclosure relates to a method of manufacturing a hollow product. More particularly, the present disclosure relates to a method of manufacturing a hollow product using a draft angle.

BACKGROUND ART

FIG. 1 illustrates a related art hollow product 10. The hollow product 10 may be made of a cast product including a hollow tube 15. The hollow product 10 may be formed in a circular pipe shape. The hollow tube 15 may be formed to extend from a first side 16 disposed at an upper part of the hollow product 10 to the inside of the hollow product 10. The hollow tube 15 inside the hollow product 10 may be formed to extend along the inside of an outer wall of the hollow product 10. The hollow tube 15 inside the hollow product 10 may have a coil spring shape. The hollow tube 15 inside the hollow product 10 may be formed to extend to a second side 17 disposed at a lower part of the hollow product 10. A longitudinal direction of the hollow tube 15 may be a direction in which the hollow tube 15 extends from the first side 16 to the second side 17. The hollow tube 15 may be formed in the form of a circular pipe.

FIG. 2 is a cross-sectional view illustrating the related art hollow product 10 and a core 20. In order to make the hollow product 10 of the circular pipe shape, the core 20 may be disposed at the center of a mold (not shown). The core 20 may have a form in which a center line CL extending in an up-down direction is used as a rotation axis. The core 20 may include a first upper surface 21 perpendicular to the center line CL, an outer surface 23 that is parallel to the center line CL and extends downward from a perimeter of the first upper surface 21, and a second upper surface 22 that is perpendicular to the center line CL and extends from a lower end of the outer surface 23 in a direction away from the center line CL. A longitudinal direction of the outer surface 23 may be the up-down direction.

Thereafter, the hollow tube 15 may be installed at a position spaced apart from the outer surface 23 of the core 20. An inner surface of the mold may be disposed at a position spaced apart from an outer surface of the hollow tube 15. The hollow product 10 may be molded by pouring a molten metal into the mold. The hollow product 10 may include an inner surface 13 formed to extend from the lower end of the outer surface 23 of the core 20 along the longitudinal direction of the outer surface 23 of the core 20, an upper surface 11 formed to extend from an upper end of the inner surface 13 in the direction away from the center line CL, a lower surface 12 formed to extend from a lower end of the inner surface 13 in the direction away from the center line CL, and outer surface 14 connecting an outer perimeter of the upper surface 11 and an outer perimeter of the lower surface 12.

In order to obtain the finished hollow product 10, it is necessary to remove the core 20 disposed inside the hollow product 10. However, since the hollow product 10 and the core 20 of FIG. 2 are configured such that the center line CL and the outer surface 23 of the core 20 are parallel to each other and the inner surface 13 of the hollow product 10 is in direct contact with the outer surface 23 of the core 20, a sufficient draft angle for taking the core 20 out of the hollow product 10 is not formed. In this case, there is a problem in that it is difficult to remove the core 20 from the hollow product 10.

-   [Patent Document 1] Korean Patent No. 10-1761677

DISCLOSURE Technical Problem

An object of the present disclosure is to address the above-described and other problems.

Another object of the present disclosure is to provide a core having a draft angle.

Another object of the present disclosure is to provide a method of manufacturing a hollow product using a core having a draft angle.

Another object of the present disclosure is to provide a carrier having a draft angle.

Another object of the present disclosure is to provide a method of manufacturing a hollow product using a carrier having a draft angle.

Another object of the present disclosure is to provide a clip having a draft angle.

Another object of the present disclosure is to provide a method of manufacturing a hollow product using a clip having a draft angle.

Technical Solution

In order to achieve the above-described and other objects, in one aspect of the present disclosure, there is provided a method of manufacturing a hollow product using a core having a draft angle, wherein the core is formed to protrude in one direction and has an outer surface at a perimeter of a protruding portion of the core, the outer surface of the core forms a slope with respect to the one direction, and a cross-sectional area of the core decreases as the core goes toward a protruding direction, the method comprising disposing a mold to be spaced apart from the outer surface of the core, disposing a hollow tube between the core and the mold, injecting a molten metal into a space between the core and the mold, and removing the core when the molten metal is solidified and the hollow product is molded.

Advantageous Effects

Effects of a method of manufacturing a hollow product using a draft angle according to the present disclosure are described as follows.

According to at least one embodiment of the present disclosure, the present disclosure can provide a core that is easily separated from a hollow product due to a draft angle of the core.

According to at least one embodiment of the present disclosure, the present disclosure can provide a carrier that is easily separated from a core due to a draft angle of the carrier.

According to at least one embodiment of the present disclosure, the present disclosure can provide a clip that is easily separated from a hollow product due to a draft angle of the clip.

Additional scope of applicability of the present disclosure will become apparent from the detailed description given blow. However, it should be understood that the detailed description and specific examples such as embodiments of the present disclosure are given merely by way of example, since various changes and modifications within the spirit and scope of the present disclosure will become apparent to those skilled in the art from the detailed description.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a related art hollow product 10.

FIG. 2 is a cross-sectional view illustrating a related art hollow product 10 and a core 20.

FIG. 3 is an exploded cross-sectional view illustrating a core 120 and a carrier 130 according to an embodiment of the present disclosure.

FIG. 4 is a cross-sectional view illustrating the core 120 and the carrier 130 of FIG. 3 and a hollow product 110 molded using them.

FIG. 5 is a cross-sectional view illustrating a core 220 and a hollow product 210 molded using the same according to another embodiment of the present disclosure.

FIG. 6 is an exploded cross-sectional view illustrating a core 320, a clip 340, and a hollow tube 315 installed in the clip 340 according to another embodiment of the present disclosure.

FIG. 7 is a plan view illustrating the core 320, the clip 340, and the hollow tube 315 of FIG. 6 .

FIG. 8 is a cross-sectional view illustrating the core 320, the clip 340, and the hollow tube 315 of FIG. 6 and a hollow product 310 molded using core 220.

FIG. 9 is a plan view illustrating the core 320, the clip 340, the hollow tube 315, and the hollow product 310 of FIG. 8 .

MODE FOR INVENTION

Reference will now be made in detail to embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In general, a suffix such as “module” and “unit” may be used to refer to elements or components. Use of such a suffix herein is merely intended to facilitate description of the present disclosure, and the suffix itself is not intended to give any special meaning or function. It will be noted that a detailed description of known arts will be omitted if it is determined that the detailed description of the known arts can obscure the embodiments of the disclosure. The accompanying drawings are used to help easily understand various technical features and it should be understood that embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings.

The terms including an ordinal number such as first, second, etc. may be used to describe various components, but the components are not limited by such terms. The terms are used only for the purpose of distinguishing one component from other components.

When any component is described as “being connected” or “being coupled” to other component, this should be understood to mean that another component may exist between them, although any component may be directly connected or coupled to the other component. In contrast, when any component is described as “being directly connected” or “being directly coupled” to other component, this should be understood to mean that no component exists between them.

A singular expression can include a plural expression as long as it does not have an apparently different meaning in context.

In the present disclosure, terms “include” and “have” should be understood to be intended to designate that illustrated features, numbers, steps, operations, components, parts or combinations thereof are present and not to preclude the existence of one or more different features, numbers, steps, operations, components, parts or combinations thereof, or the possibility of the addition thereof.

In the drawings, sizes of the components may be exaggerated or reduced for convenience of explanation. For example, the size and the thickness of each component illustrated in the drawings are arbitrarily illustrated for convenience of explanation, and thus the present disclosure is not limited thereto unless specified as such.

If any embodiment is implementable differently, a specific order of processes may be performed differently from the order described. For example, two consecutively described processes may be performed substantially at the same time, or performed in the order opposite to the described order.

FIG. 3 is an exploded cross-sectional view illustrating a core 120 and a carrier 130 according to an embodiment of the present disclosure.

The core 120 may have a form in which a center line CL extending in an up-down direction is used as a rotation axis. The core 120 may have a shape in which a portion is formed to protrude upward. The core 120 may include an outer surface 123 formed around the protruding portion, a first upper surface 121 formed at an upper end of the outer surface 123, and a second upper surface 122 formed at a lower end of the outer surface 123.

The core 120 may include the first upper surface 121 perpendicular to the center line CL. The core 120 may include the outer surface 123 extending downward from a perimeter of the first upper surface 121. The outer surface 123 may be formed to move away from the center line CL as it goes toward the lower side. The core 120 may include the second upper surface 122 that is perpendicular to the center line CL and extends from the lower end of the outer surface 123 in a direction away from the center line CL.

As illustrated in FIG. 3 , the outer surface 123 of the core 120 may have a slope with respect to the center line CL. An angle forming the slope may be referred to as a first angle θ1. The first angle θ1 may be formed such that a cross-sectional area of the core 120 decreases as the core 120 goes toward the upper side. The first angle θ1 may be referred to as a draft angle.

The carrier 130 may have a form in which the center line CL extending in the up-down direction is used as a rotation axis. The carrier 130 may include an upper surface 131 that is perpendicular to the center line CL and extends from a position spaced apart from the center line CL in the direction away from the center line CL. The carrier 130 may include an outer surface 134 that is parallel to the center line CL and extends downward from an outer perimeter of the upper surface 131. A longitudinal direction of the outer surface 134 may be the up-down direction. The carrier 130 may include a lower surface 132 that extends from a lower end of the outer surface 134 in a direction approaching to the center line CL. The carrier 130 may include an inner surface 133 that connects an inner perimeter of the upper surface 131 and an inner perimeter of the lower surface 132. That is, a core insertion hole 135 may be formed inside the carrier 130. A diameter of a lower end of the core insertion hole 135 may be equal to a diameter of a lower end of the outer surface 123 of the core 120.

As illustrated in FIG. 3 , an angle between the inner surface 133 and the outer surface 134 of the carrier 130 may be referred to as a second angle θ2. The second angle θ2 may be equal to the first angle θ1. The second angle θ2 may be referred to as a draft angle. That is, when the carrier 130 is fitted to the core 120, the inner surface 133 of the carrier 130 and the outer surface 123 of the core 120 may be in close contact with each other. Hence, a molten metal can be prevented from penetrating between the core 120 and the carrier 130.

The carrier 130 may be manufactured by forming a hollow in a cylindrical extruded material and machining the inner surface 133 of the hollow. The carrier 130 may be manufactured by rolling a flat plate material having the inner surface 133 and the outer surface 134 into a circular shape. A slope of the inner surface 133 of the carrier 130 may be formed to be same as a slope of the outer surface 123 of the core 120, and a slope of the outer surface 134 of the carrier 130 may be formed to be parallel to the center line CL.

A material of the carrier 130 may be a metal or a non-ferrous metal.

FIG. 4 is a cross-sectional view illustrating the core 120 and the carrier 130, and a hollow product 110 molded using them. A mold may be disposed to be spaced apart from the outer surface 134 of the carrier 130. A hollow tube 115 may be disposed between the outer surface 134 of the carrier 130 and the mold. The molten metal may be injected into a remaining space between the outer surface 134 of the carrier 130 and the mold. When the molten metal is solidified, the hollow product 110 including the hollow tube 115 may be molded.

The hollow product 110 may include an inner surface 113 that extends from a lower end of the outer surface 134 of the carrier 130 along the longitudinal direction of the outer surface 134 of the carrier 130. The hollow product 110 may include an upper surface 111 that extends from an upper end of the inner surface 113 in the direction away from the center line CL. The hollow product 110 may include a lower surface 112 that extends from a lower end of the inner surface 113 in the direction away from the center line CL. The hollow product 110 may include an outer surface 114 that connects an outer perimeter of the upper surface 111 and an outer perimeter of the lower surface 112.

Referring to FIGS. 3 and 4 , since the draft angles θ1 and θ2 are formed in the outer surface 123 of the core 120 and the inner surface 133 of the carrier 130, the core 120 can be easily taken out of the carrier 130. Hence, the hollow product 110 including the carrier 130 can be formed.

Unlike the above description, the carrier 130 can be easily removed from the hollow product 110. When the core 120 is removed, the carrier 130 may be elastically deformed since the core insertion hole 135 of the carrier 130 becomes empty. Hence, the carrier 130 can be easily taken out of the hollow product 110.

FIG. 5 is a cross-sectional view illustrating a core 220 and a hollow product 210 molded using the same according to another embodiment of the present disclosure.

The core 220 may have a form in which a center line CL extending in an up-down direction is used as a rotation axis. The core 220 may have a shape in which a portion is formed to protrude upward. The core 220 may include an outer surface 223 formed around the protruding portion, a first upper surface 221 formed at an upper end of the outer surface 223, and a second upper surface 222 formed at a lower end of the outer surface 223.

The core 220 may include the first upper surface 221 perpendicular to the center line CL. The core 220 may include the outer surface 223 extending downward from a perimeter of the first upper surface 221. The outer surface 223 may be formed to move away from the center line CL as it goes toward the lower side. The core 220 may include the second upper surface 222 that is perpendicular to the center line CL and extends from the lower end of the outer surface 223 in a direction away from the center line CL.

As illustrated in FIG. 5 , the outer surface 223 of the core 220 may have a slope with respect to the center line CL. An angle forming the slope may be referred to as a third angle θ3. The third angle θ3 may be formed such that a cross-sectional area of the core 220 decreases as the core 220 goes toward the upper side. The third angle θ3 may be referred to as a draft angle. A longitudinal direction of the outer surface 223 may be a direction that is inclined with respect to the center line CL by the third angle θ3 in the up-down direction.

A mold may be disposed to be spaced apart from the outer surface 223 of the core 220. A hollow tube 215 may be disposed between the outer surface 223 of the core 220 and the mold. A molten metal may be injected into a remaining space between the outer surface 223 of the core 220 and the mold. When the molten metal is solidified, the hollow product 210 including the hollow tube 215 may be molded.

The hollow product 210 may include an inner surface 213 that extends from a lower end of the outer surface 223 of the core 220 along the longitudinal direction of the outer surface 223 of the core 220. That is, an angle between the inner surface 213 and the center line CL may be the same as the third angle θ3. The hollow product 210 may include an upper surface 211 that extends from an upper end of the inner surface 213 in the direction away from the center line CL. The hollow product 210 may include a lower surface 212 that extends from a lower end of the inner surface 213 in the direction away from the center line CL. The hollow product 210 may include an outer surface 214 that connects an outer perimeter of the upper surface 211 and an outer perimeter of the lower surface 212.

Since the same draft angle θ3 is formed in the outer surface 223 of the core 220 and the inner surface 213 of the hollow product 210, the core 120 can be easily taken out of the hollow product 210.

FIG. 6 is an exploded cross-sectional view illustrating a core 320, a clip 340, and a hollow tube 315 installed in the clip 340 according to another embodiment of the present disclosure. FIG. 7 is a plan view illustrating the core 320, the clip 340, and the hollow tube 315.

The core 320 may have a form in which a center line CL extending in an up-down direction is used as a rotation axis. The core 320 may have a shape in which a portion is formed to protrude upward. The core 320 may include an outer surface 323 formed around the protruding portion, a first upper surface 321 formed at an upper end of the outer surface 323, and a second upper surface 322 formed at a lower end of the outer surface 323.

The core 320 may include the first upper surface 321 perpendicular to the center line CL. The core 320 may include the outer surface 323 extending downward from a perimeter of the first upper surface 321. The outer surface 323 may be formed to move away from the center line CL as it goes toward the lower side. The core 320 may include the second upper surface 322 that is perpendicular to the center line CL and extends from the lower end of the outer surface 323 in a direction away from the center line CL.

As illustrated in FIG. 6 , the outer surface 323 of the core 320 may have a slope with respect to the center line CL. An angle forming the slope may be referred to as a fourth angle θ4. The fourth angle θ4 may be formed such that a cross-sectional area of the core 320 decreases as the core 320 goes toward the upper side. The fourth angle θ4 may be referred to as a draft angle.

The clip 340 may have a form in which the center line CL extending in the up-down direction is used as a rotation axis. As illustrated in FIG. 7 , the clip 340 may be formed only in a partial area using the center line CL as the rotation axis. The clip 340 may be formed on the left side and the right side of the core 320.

The clip 340 may include an upper surface 341 that is perpendicular to the center line CL and extends from a position spaced apart from the center line CL in the direction away from the center line CL. The clip 340 may include an outer surface 344 that is parallel to the center line CL and extends downward from an outer perimeter of the upper surface 341. A longitudinal direction of the outer surface 344 may be the up-down direction. The clip 340 may include a lower surface 342 that extends from a lower end of the outer surface 344 in a direction approaching to the center line CL. The clip 340 may include an inner surface 343 that connects an inner perimeter of the upper surface 341 and an inner perimeter of the lower surface 342. The hollow tube 315 may be fixed to the outer surface 344 of the clip 340.

As illustrated in FIG. 6 , an angle between the inner surface 343 and the outer surface 344 of the clip 340 may be referred to as a fifth angle θ5. The fifth angle θ5 may be equal to the fourth angle θ4. The fifth angle θ5 may be referred to as a draft angle. That is, when the clip 340 is installed in the core 320, the inner surface 343 of the clip 340 and the outer surface 323 of the core 320 may be in close contact with each other. Hence, a molten metal can be prevented from penetrating between the core 320 and the clip 340.

FIG. 8 is a cross-sectional view illustrating the core 320, the clip 340, and the hollow tube 315, and a hollow product 310 molded using them. FIG. 9 is a plan view illustrating the core 320, the clip 340, the hollow tube 315, and the hollow product 310.

The hollow tube 315 may be fixed to the outer surface 344 of the clip 340. The mold may be disposed to be spaced apart from an outer surface of the hollow tube 315, the outer surface 344 of the clip 340, and the outer surface 323 of the core 320. The molten metal may be injected into a remaining space between the outer surface 323 of the core 320 and the mold. When the molten metal is solidified, the hollow product 210 including the clip 340 and the hollow tube 315 may be molded.

A height of the hollow product 310 may be the same as a height of the clip 340. The height of the hollow product 310 may be greater than the height of the clip 340. The hollow product 310 may be formed so that the fixed hollow tube 315 of the clip 340 is covered. The hollow product 310 formed in a portion not having the clip 340 may have the same shape as the hollow product 210 described above.

A material of the clip 340 may be a metal or a non-ferrous metal. The material of the clip 340 may be the same as a material of the molten metal. That is, the material of the clip 340 may be the same as a material of the hollow product 310. FIG. 9 illustrates distinguishably a boundary between the hollow product 310 and the clip 340 for convenience of explanation. However, after going through a high-pressure casting process using the molten metal, an external surface of the clip 340 may be melted in the molten metal, and the boundary between the clip 340 and the hollow product 310 may disappear.

Referring to FIGS. 8 and 9 , since the outer surface 323 of the core 320 and the inner surface 343 of the clip 340 have the draft angles θ4 and θ5, respectively, the core 320 can be easily taken out of the clip 340. Since the outer surface 323 of the core 320 and an inner surface (not shown) of the hollow product 310 each have the draft angle θ4, the core 320 can be easily taken out of the hollow product 310.

Some embodiments or other embodiments of the present disclosure described above are not mutually exclusive or distinct from each other. Configurations or functions of some embodiments or other embodiments of the present disclosure described above can be used together or combined with each other.

It is apparent to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the spirit and essential features of the present disclosure. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the present disclosure should be determined by rational interpretation of the appended claims, and all modifications within an equivalent scope of the present disclosure are included in the scope of the present disclosure. 

1. A method of manufacturing a hollow product using a core having a draft angle, wherein the core is formed to protrude in one direction and has an outer surface at a perimeter of a protruding portion of the core, the outer surface of the core forms a slope with respect to the one direction, and a cross-sectional area of the core decreases as the core goes toward a protruding direction, the method comprising: disposing a mold to be spaced apart from the outer surface of the core; disposing a hollow tube between the core and the mold; injecting a molten metal into a space between the core and the mold; and removing the core when the molten metal is solidified and the hollow product is molded.
 2. The method of claim 1, wherein a carrier is installed at a perimeter of the outer surface of the core, wherein an inner surface of the carrier is in close contact with the outer surface of the core, wherein an outer surface of the carrier is formed parallel to the one direction, wherein in the disposing of the mold, the mold is disposed to be spaced apart from the outer surface of the carrier wherein in the disposing of the hollow tube, the hollow tube is disposed between the carrier and the mold, and wherein in the injecting of the molten metal, the molten metal is injected between the carrier and the mold.
 3. The method of claim 2, wherein the carrier is formed such that a hollow is formed inside a cylindrical extruded material, and an inner surface of the hollow is processed to be tapered.
 4. The method of claim 2, wherein that carrier is formed such that a plate, in which a slope of one surface is the same as a slope of the outer surface of the core and a slope of other surface is formed parallel to the one direction, is in close contact with the outer surface of the core.
 5. The method of claim 5, wherein a material of the carrier is a metal or a non-ferrous metal.
 6. The method of claim 1, wherein a clip is installed at a perimeter of the outer surface of the core, wherein an inner surface of the clip is in close contact with the outer surface of the core, wherein an outer surface of the clip is formed parallel to the one direction, and wherein the hollow tube is fixed to the outer surface of the clip.
 7. The method of claim 6, wherein a material of the clip is a metal or a non-ferrous metal.
 8. The method of claim 5, wherein the clip is formed only on a portion of the perimeter of the outer surface of the core. 